1) Field of the Invention
This invention relates to the manufacturing methods of high purity maltose and its reduced product.
2) Description of the Related Art
Maltose, 4-[.alpha.-D-glucopyranosyl]-D-glucose has been known as the main component of maltose starch syrup and used for a variety of foods because of its rich flavor.
On the other hand, maltitol, 4-[.alpha.-D-glucopyranosyl]-D-glutitol, the reduced product of the maltose, has found a variety of applications including foods, cosmetics, and medicines as it is less fermentable by the microorganisms and it contains sweet taste that is similar to sugar.
So far, it was harder to obtain high purity maltose or maltitol than to obtain high purity products of other saccharides. However, the attempts have been made to alleviate it by adopting specific saccharification method or by adopting the chromatographic separation method that has been used to improve the purity of other saccharides, to the manufacturing process of maltose or maltitol.
Among the many attempts to obtain high purity maltose or maltitol, the following are the typical cases.
(a) A method, as shown in Japanese TOKKYO-KOKAI-KOHO (18-month Publication of Unexamined Patent Application) SHOWA 57(1982)-134498 (hereinafter referred to as TOKKAISHO 57-134498), to obtain a high maltose liquid by acting .beta.-amylase and isoamylase after liquefying starch to low DE (dexitrose equivalent) with .alpha.-amylase. PA1 (b) A method, as shown in Japanese TOKKAISHO 57-209000, TOKKAISHO 58-23799, TOKKAISHO 60-67000, TOKKAISHO 62-19210, to manufacture high purity maltose containing, for instance, not less than 93%, of maltose by performing a chromatographic separation for constituent of saccharified liquid that is chiefly composed of maltose with maltose purity of 75 through 85% (in this specification, "%" means "percentage by weight" per solid substance, unless otherwise stipulated) and contains less glucose with alkali metal strong acid cation exchange resin. PA1 (c) A method, well-suited for manufacturing maltitol in the form of powder or crystal , as shown in Japanese TOKKYO-KOKOKU-KOHO (Publication of Examined Patent Application for Opposition) SHOWA 57(1982)-3356 (hereinafter referred to as TOKKOSHO 57-3356) , TOKKOSHO 56-28153, TOKKOSHO 56-28154, to prepare maltose to which hydrogen has not yet been added, by acting, enzyme and the like (maltotriose resolutive activation/maltose resolutive activation is 2.5 or more) during saccharification. PA1 (d) A method to obtain high purity maltitol--other than the method by reducing the maltose obtained through the above-mentioned methods, and undergoing several processings such as purification, separation, and crystallization--, as shown in Japanese TOKKAISHO 61-180797, by 1) liquefying the starch milk with a concentration of 25 through 457%, 2) saccharifying under the specified saccharification conditions, 3) obtaining saccharified liquid with the maltose purity of not less than 50 through 80%, 4) adding hydrogen to it, 5) performing a chromatographic separation, 6) obtaining sugar-alcohol liquid with the maltitol purity of 87 through 97.5%, 7) concentrating, and then 8) crystallizing it. PA1 1. A method to manufacture high purity maltose using the following three processes. PA1 2. A method to manufacture high purity maltose as described in paragraph 1 above in which the No. 1 process is a process to be liquefied by heating the starch aqueous solution (with concentration 5 through 15%) to the starch paste. PA1 3. A method to manufacture high purity maltose as described in paragraph 1 or 2 above in which the No. 3 process is a process to continue saccharification, for 10 through 48 hours from the beginning of the No. 2 process, by using maltogenic-.alpha.-amylase, 1 through 24 hours after starting the No. 2 process. PA1 4. A method to manufacture high purity maltose as described in paragraph 1, 2 or 3 above, to obtain saccharic liquid containing 94.5% by weight or more of maltose per solid substance in the liquid by adjusting pH not more than 4.5, after the completion of No. 3 process, removing water insoluble components, hydrolyzing the dextrin in the liquid by using liquefying enzyme, and then purifying it. PA1 5. A method to manufacture high purity maltose as described in paragraph 1 or 2 above in which the No. 3 process is a process to obtain saccharic liquid containing 94.5% by weight or more of maltose per solid substance in the liquid, by continuing saccharification, for 10 through 48 hours after the start of No. 2 process, for the saccharic liquid obtained after adjusting pH of the liquid to not more than 4.5 and removing the residue, 1 through 24 hours after the start of No. 2 process, by using maltogenic-.alpha.-amylase; thereafter, by hydrolyzing the dextrin in the liquid by using liquefying enzyme, filtrating and purifying. PA1 6. A method to manufacture high purity maltose as described in paragraph 1 above, in which the No. 2 process is a process to saccharize the obtained liquefied substance to a maltose purity of 70% by weight or more in the solid part by using at least two enzymes selected from the group consisting of .beta.-amylase, pullulanase and isoamylase, whereas, the No. 3 process is a process to saccharize the saccharification liquid obtained in the No. 2 process by using maltogenic-.alpha.-amylase until the value of the following formula (hereinafter may be referred simply to as Formula-1) becomes not more than 8: ##EQU1## 7. A method to manufacture high purity maltitol using the following four processes. PA1 8. A method to manufacture high purity maltitol as described in paragraph 7 above in which the No. 1 process is a process to be liquefied by heating the starch aqueous solution (with concentration 5 through 15%) to the starch paste. PA1 9. A method to manufacture high purity maltitol as described in paragraph 7 or 8 above in which the No. 3 process is a process to continue saccharification, for 10 through 48 hours from the beginning of the No. 2 process, by using maltogenic-.alpha.-amylase, 1 through 24 hours after starting the No. 2 process. PA1 10. A method to manufacture high purity maltitol as described in paragraph 7, 8, or 9 above, to obtain saccharic liquid containing 94.5% by weight or more of maltose per solid substance in the liquid by adjusting pH not more than 4.5, after the completion of No. 3 process, removing water insoluble components, hydrolyzing the dextrin in the liquid by using liquefying enzyme, and then purifying it. PA1 11. A method to manufacture high purity maltitol as described in paragraph 7 or 8 above in which the No. 3 process is a process to obtain saccharic liquid containing 94.5% by weight or more of maltose per solid substance in the liquid, by continuing saccharification, for 10 through 48 hours after the start of No. 2 process, for the saccharic liquid obtained after adjusting pH of the liquid to not more than 4.5 and removing the residue, 1 through 24 hours after the start of No. 2 process, by using maltogenic-.alpha.-amylase; thereafter, by hydrolyzing the dextrin in the liquid by using liquefying enzyme, filtrating and purifying. PA1 12. A method to manufacture high purity maltitol as described in paragraph 7 above, in which the No. 2 process is a process to saccharize the obtained liquefied substance to a maltose purity of 70% by weight or more in the solid part by using at least two enzymes selected from the group consisting of .beta.-amylase, pullulanase and isoamylase, whereas, the No. 3 process is a process to saccharize the saccharification liquid obtained in the No. 2 process by using glucoamylase until the value of the Formula-1 becomes not more than 8, and No. 4 process is a process to reduce the saccharification liquid after the No. 3 process and separate the obtained reduced product into the fractions of which main components are maltitol and other fractions by the chromatographic separation method. PA1 13. A method to manufacture high purity maltitol as described in paragraph 12 above in which an adsorbent used for the chromatographic separation is a sodium type ion exchanger. PA1 14. A method to manufacture high purity maltose using the following three processes. PA1 15. A method to manufacture high purity maltose as described in paragraph 14 above in which the concentration of ground starch is 10 through 30% by weight and liquefying enzyme is deactivated when DE after liquefaction is not more than 10, in the No. 1 process. PA1 16. A method to manufacture high purity maltose as described in paragraph 14 above in which the No. 3 process is a process to saccharize by using maltogenic-.alpha.-amylase within 36 after the start of the No. 2 process. Further, 1 through 48 hours after the beginning of the No. 2 process, saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid having maltose purity of 75 through 90 by weight and limiting the value to not more than 7 when calculating with Formula-1. PA1 17. A method to manufacture high purity maltose as described in paragraph 14 or 15 above in which the No. 3 process is a process to saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid 1 through 10 hours after the start of the No. 2 process. Further saccharize by using maltogenic-.alpha.-amylase at the rate of 1 through 20 units per 1 g of substrate solid having maltose purity of 75 through 88% by weight and limiting the value to not more than 8 when calculating with Formula-1. PA1 18. A method to manufacture high purity maltose as described in paragraph 14 or 15 above in which the No. 3 process is a process to saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid. Further saccharize by using glucoamylase at the rate of 0.1 through 10 units per 1 g of substrate solid having maltose purity of 75 through 88% by weight and limiting the value to not more than 8 when calculating with Formula-1. PA1 19. A method to manufacture high purity maltitol using the following four processes. PA1 20. A method to manufacture high purity maltitol as described in. paragraph 19 in which the concentration of ground starch is 10 through 30% by weight and liquefying enzyme is deactivated when DE after liquefaction is not more than 10, in the No. 1 process. PA1 21. A method to manufacture high purity maltitol as described in paragraph 19 above in which the No. 3 process is a process to saccharize by using maltogenic-.alpha.-amylase within 36 hours after the start of the No. 2 process. Further saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid having maltose purity of 75 through 90% by weight and limiting the value to not more than 7 when calculating with Formula-1. PA1 22. A method to manufacture high purity maltitol as described in paragraph 19 or 20 above in which the No. 3 process is a process to saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid 1 through 10 hours after the start of the No. 2 process. Further saccharize by using maltogenic-.alpha.-amylase at the rate of 1 through 20 units per 1 g of substrate solid having maltose purity of 75 through 88% by weight and limiting the value to not more than 8 when calculating with Formula-1. PA1 23. A method to manufacture high purity maltitol as described in paragraph 19 or 20 above which the No. 3 process is a process to saccharize by using liquefying enzyme at the rate of 1 through 20 units per 1 g of substrate solid. Further saccharize by using glucoamylase at the rate of 0.1 through 10 units per 1 g of substrate solid having maltose purity of 75 through 88% by weight and limiting the value to not more than 8 when calculating with Formula-1.
However, there are many problems to be solved with the conventional methods, and are not satisfactory as methods to manufacture high purity maltose or maltitol on a commercial basis.
For example, in the above-mentioned method (a), it is necessary to suppress, in liquefying the starch, the DE as low as possible. To put it concretely, it is necessary to suppress the DE not more than 2, preferably, 0.5 through 1.0 so as to obtain high purity maltose or maltitol.
To satisfy this DE value and values during the following processings, it is necessary to limit the raw material starch to expensive underground starch (potato starch, etc.) and suppress the liquefication concentration not more than 20% which is the lower value than that used for the conventional manufacturing process for high-maltose.
As a result, this method requires very large saccharification tank than that used for manufacturing high-maltose syrup or glucose syrup that are produced and distributed on a large scale. At the same time, it is necessary to concentrate a large amount of water, leading to a drawback of an increased concentration cost.
The above-mentioned method (b) is a method that allows to use inexpensive ground starch. The processing that is responsible for increasing the purity of maltose is a method to separate maltose from DP 3 or more (degree of polymerization), that is oligosaccharides of trisaccharide or more. In this method, however, it is extremely difficult to perform a separation because the molecular weight ratio of maltose and maltotriose is small and there is a small difference in the nature necessary for other separations,
For this reason, a separation column with a great deal of capacity is required. A great deal of elution water is needed for separation. Thus, it requires a lot of concentration cost. These are the defects of this method. Furthermore, an entry of impurities such as glucose into maltose fraction, that takes place often because the separation is difficult, keeps us from obtaining high purity maltose.
The point of the above-mentioned. method (c) is that enzyme (maltotriose resolutive activation/maltose resolutive activation is 2.5 or more) and the like are acted during the saccharification. However, the defect is that it is difficult to obtain the enzyme because specific enzyme is used during saccharification. Another defect is that maltitol has to be produced from high purity maltose saccharification liquid obtained through saccharification by stopping the liquefaction at the level of around DE 1, because the increased glucose (because maltose is decomposed) keeps the yield of maltose at a low level.
In the above-mentioned method (d), the liquid used for separation is a mixture of sorbitol, maltitol, and sugar-alcohol of DP 3 or more. To take out a separation chiefly composed of maltitol, eight-column chromatographic separation unit has be operated in an extremely complicated manner.
Nonetheless, the separation status of each saccharin component is poor. Consequently, about 8% of maltotriitol can be seen in a fraction chiefly composed of maltitol.
The drawback of this method is that a contamination of sugar-alcohol of DP 3 or more checks the crystallization of maltitol, leading to a longer crystallization process and a lower yield of maltitol.
Because, moreover, the calcium type ion exchanger used for separation has a very strong adsorbing force against sorbitol, its elution is extremely slow as compared with maltitol or sugar-alcohol of DP 3 or more. As a result, chromatographic separation requires elution water five times the amount of raw material saccharification water. This means it is necessary to concentrate and remove a large amount of water, which is extremely inconvenient matter when viewed commercially.
Hence, a method for manufacturing high purity maltose and its reduced product which can solve the above-mentioned problems has been required.